I was brought up listening to Leadbelly, as my father was a huge fan of American blues and jazz. I took and taught numerous Equal Opps courses in the 90s, and have read several books on race relations and sexism, but I've only heard the term 'woke' in the past few years (maybe since BLM?). I remember looking it up when reading Don't Call Us Dead, which was published in 2017, although it was probably later than that when I read it. I'm not very good at remembering timelines for things that don't seem important in themselves, and coming across a word that expresses something that has been around forever (an awareness of injustice) didn't stick in my mind.
Anyway, I don't think that the fact that the word was coined by Leadbelly, whether or not we know who he was or not, or how long any of us has been aware of it is relevant, really. It's how the term is used now that matters.
(Kandinski, he was a blues/folk singer from the Southern states of America at the time of Woody Guthrie. He has influenced many modern singers. Here is a video of him singing a posthumous 'duet' with Kurt Cobain